In this research, we examine the difference between five vote-by-mail policies in place in the 2018 midterm elections. We use statistical modeling to understand the effects of different vote-by-mail policies nationwide and estimate what might have changed in 2018 based on different voting systems. In general, we find that turnout increases as states move along the vote-by-mail policy continuum, removing administrative obstacles for voters in the process. Additionally, turnout gains are largest when counties progress several steps from more restrictive policies to less restrictive policies, and the Vote at Home policy has the most potential to impact young voters.